#include <Arduino.h>


int pin_list[] = {12, 13, 14, 27};

int led_size = sizeof(pin_list) / sizeof(pin_list[0]);


void setup() {

    for (int i = 0; i < led_size; i++) {
      pinMode(pin_list[i], OUTPUT);
    }

}


void loop() {
  for (int i = 0; i < led_size; i++) {
    digitalWrite(pin_list[i], HIGH);
    delay(500);
    digitalWrite(pin_list[i], LOW);
  }
}
